The pocket-sized HP 12C has been an indispensible tool to a generation of financial analysts, accountants, investment advisers, and others who run complex financial calculations. And HP is sticking with what works: The new version, the HP 12C Platinum, offers only minor changes, including a better battery and easier data entry... If I had to use a financial model or run a complicated financial calculation repeatedly with only minor variations, I would fire up a spreadsheet. But spreadsheet models or calculation templates take a lot of time and effort to create, and they are very inefficient for a one-time calculation. That's where calculators shine.